tensioning wheel moves frame dropouts together
- Thread starter silva
- Start date
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PedallingNowhereSlowly
Well-Known Member
What's the frame made out of?
And what type of frame is it? (Road, MTB etc..)
The key thing you ideally want to know, is the over-locknut distance (OLD) or hub spacing the frame is designed for. There are some standards, and the standard that applies will depend on the type and the age of the frame.
It might be, that one of your chain/seat stays is bent out of alignment ... there are some methods you can employ, using lengths of string and taking measurements, to get an indication of the frame alignment. There's some useful YouTube videos on doing this but I sadly can't remember which channel made them.
It's also worth having a good look at the frame - especially the seat and chain stays as well as the areas around the bottom bracket and where the top tube is welded to the seat tube to make sure there are not any cracks in the frame.
It might be that you just need to add a spacer to your rear hub because it has a smaller OLD on account of being designed for a narrower set frame. Or it might be that this is an early sign of the frame failing?
And what type of frame is it? (Road, MTB etc..)
The key thing you ideally want to know, is the over-locknut distance (OLD) or hub spacing the frame is designed for. There are some standards, and the standard that applies will depend on the type and the age of the frame.
It might be, that one of your chain/seat stays is bent out of alignment ... there are some methods you can employ, using lengths of string and taking measurements, to get an indication of the frame alignment. There's some useful YouTube videos on doing this but I sadly can't remember which channel made them.
It's also worth having a good look at the frame - especially the seat and chain stays as well as the areas around the bottom bracket and where the top tube is welded to the seat tube to make sure there are not any cracks in the frame.
It might be that you just need to add a spacer to your rear hub because it has a smaller OLD on account of being designed for a narrower set frame. Or it might be that this is an early sign of the frame failing?
The wheel is mounted with bolts with hexagon head - not with nuts.
The hub is Surly Ultra 13x10mm 36G single speed, disc (I assume that 13 is 130 mm)
The distance between dropouts is 135 mm (I just measured)
The hub spec doesn't match the frame spec, which explains the movement I see.
So everytime the wheels mount get losened (tyre replacement, cog flip or replacement, cleaning so quite some times), the frames forks bend back outward to then be forced back inward, to stay there, under a stress, if I could name it like that, for most of the time (= the time the wheel is mounted / bike is parked/used)
It could be that a frame is designed to tolerate this, so no worries.
But it could also be that the near-permanent stress ends in a crack, which is then a reason to bother.
The hub is Surly Ultra 13x10mm 36G single speed, disc (I assume that 13 is 130 mm)
The distance between dropouts is 135 mm (I just measured)
The hub spec doesn't match the frame spec, which explains the movement I see.
So everytime the wheels mount get losened (tyre replacement, cog flip or replacement, cleaning so quite some times), the frames forks bend back outward to then be forced back inward, to stay there, under a stress, if I could name it like that, for most of the time (= the time the wheel is mounted / bike is parked/used)
It could be that a frame is designed to tolerate this, so no worries.
But it could also be that the near-permanent stress ends in a crack, which is then a reason to bother.
- Location
- Inside my skull
How many years has it been doing this?
That was what lead to my question:
The frame tube below, left is bottom bracket zone, right goes to the dropout, drivetrain side, with wheel location thus upwards. It is cracked to the inside, being the direction the tube goes when tensioning the wheels mount, that 5 mm.
It could be vice versa, that the frame failed because of missing spacer or wrongly chosen hub spec.
Despite the crack, the distance between the ends is still that 135, and I can push them abit together, after which they veer back to that 135 mm. The crack is at the outer side of the tube, the rest of the cross section is apparently strong enough to make the dropout veer back (so with no wheel mounted - free) to the 135 mm distance.
That the crack sits on the outer half of the tube is an important detail here, because if a part of the current (=post-fail) measured drop out distance would result from the crack, it would have moved the tube inwards instead of outwards, and the symptom would be that I would need to pull the dropouts away from eachother / more open, to get the wheel in. This is the opposite, and it also has always been that way since acquiring the bike, back in 2017.
In aboves crack explanation scenario, inserting the same wheel in a new same frame, could deliver a repeat story, and in order to avoid that, the hub's 130 mm should be complemented to the frames 135 mm. A spacer, washers (both sides). For that solution I see a problem: the Surly hub has 5 mm - protruding ends (where the mounting bolts with hexagon head get screwed in, and the wheel rests on those ends (= mating surfac, so putting spacers there = taking away wheels supporting surface.
This is a web pic of that Surly hub, taken from:
https://surlybikes.com/parts/ultra_new_hubs
Those flanges on both sides have roughed surfaces, to avoid slipping.
Abit like the more common nuts.
So it doesn't look like a spacers based solution is possible here.
Also, if mounting a wheel moves frame parts (the dropouts), if one gets moved over a different distance than the other, the rear wheel ends up NOT in the middle of the frame. This may explain another problem the bike suffers since acquirement: the rear tyre, a 62 mm Schwalbe "super-moto-x" wears out of center away from the drivetrain side. When the tyres middle profile edge one side becomes 0 mm, the other side is still 2 mm, after a couple years I started to flip the tyre, giving me a season longer life, on a life averaging 1 year.
Since I bought the bike as new, from dealer and brands production.
https://surlybikes.com/parts/ultra_new_hubs
That 135 mm is named there as "MTB spacing".
Mine is 36 holes, not listed there, but I would assume 135 mm was available then back in 2017 too, MTB is not like a small niche market. Frame has dropout distance 135 mm, producent of my bike mounts 130 mm hub, while same hub is avail in the compatible 135 mm.
Same year of the bikes purchase, I ordered a spare same rear wheel.
IN CASE the cracks' cause is this, dropouts forced 5 mm closer, it's hard to see a solution other than replacing the hubs (including the one of the spare wheel) with 135 mm ones.
- Location
- Inside my skull
Which was what month and year?
Yellow Saddle
Guru
- Location
- Loch side.
Dont feed the animals. You know where this is going.
I
Some months after the bikes delivery, I ordered a spare rear wheel, is also a 130 mm hub.
Mentioned on the invoice, also measured like that, today.
2017, delivery september.
Some months after the bikes delivery, I ordered a spare rear wheel, is also a 130 mm hub.
Mentioned on the invoice, also measured like that, today.
The hub size is irrelevant here. The frame has had it. The crack on the stay is terminal, and potentially dangerous. skip it.
You could strip all the components and find yourself a new frame and build the bike up. As long as the OLN is 130mm.
You could strip all the components and find yourself a new frame and build the bike up. As long as the OLN is 130mm.
PedallingNowhereSlowly
Well-Known Member
The OP is trying to work out what the root cause of this issue was because either:
It's a 7 year old frame; I've no idea what mileage it's covered and how laiden it's been for that mileage but temptation here would be to chalk this up to experience and replace. The drop out spacing might have been a contributing factor to the frames failure mode but if it's been well used in that 7 years, I'd say it was a fair innings. Especially if the frame was made of aluminium.
With any replacement frame, you can check the OLN distance in the specification and ensure it matches the wheels/hubs you already own. Probably worth measuring the hubs you have (and making sure they are the same, given you have two) with a vernier gauge rather than speculating over specifications.
TBH, I've had bikes where there's been a couple of mm movement in the drop outs either to get the wheel in or when tensioning the nuts. These were old steel bikes I used to acquire from the tip and build up as winter commuters. I can't recall having this type of experience on anything modern.
- he has or may get potentially a the same frame as a replacement?
- he's trying to establish whether the frame was supplied with the incorrectly sized hub in the first place
It's a 7 year old frame; I've no idea what mileage it's covered and how laiden it's been for that mileage but temptation here would be to chalk this up to experience and replace. The drop out spacing might have been a contributing factor to the frames failure mode but if it's been well used in that 7 years, I'd say it was a fair innings. Especially if the frame was made of aluminium.
With any replacement frame, you can check the OLN distance in the specification and ensure it matches the wheels/hubs you already own. Probably worth measuring the hubs you have (and making sure they are the same, given you have two) with a vernier gauge rather than speculating over specifications.
TBH, I've had bikes where there's been a couple of mm movement in the drop outs either to get the wheel in or when tensioning the nuts. These were old steel bikes I used to acquire from the tip and build up as winter commuters. I can't recall having this type of experience on anything modern.
T4tomo
Legendary Member
https://www.cyclechat.net/threads/rear-wheel-scraping-noise-every-rotation.251052/post-5672222
above suggests frame is for 135mm OLD at some point OP has but a 130mm hub in it and its an Alu frame that hasn't liked it and is now farked.
